In this study, we examine the Russian automatic lunar missions “Luna-25,” “Luna-26,” and the scientific objectives and landing site of the “Luna-27″ spacecraft. The landing of “Luna-27″ is planned directly in the South Polar region, which, due to ballistic and engineering requirements, is confined to a sector extending from 51°E to 1°W in longitude and from 83°S to 79°S in latitude. This area is characterized by complex terrain, and to identify suitable landing territories, a suitability map has been created that takes into account the distribution of slopes, the degree of illumination, and visibility of Earth. A total of five sites measuring 30 × 15 km (landing ellipse) within the considered region meet such scientific and technical requirements as slope distributions of less than 7–10°, sunlight illumination of more than 35 %, and Earth visibility of more than 50 %. All landing sites are ranked by priority from 1 to 5 depending on the content of water equivalent of hydrogen (WEH) in the lunar soil. Site №1, by its characteristics, is considered the best and may be chosen as the primary landing site, while sites №2 and №3 could serve as backups. It is demonstrated that with increased landing precision, with a deviation probability from the given point up to 0.5 km, the number of suitable landing sites satisfying primarily scientific rather than engineering-technical safety criteria, which are also inherently met, significantly increases.

中文翻译：

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Luna-27 任务在月球南极地区的着陆点选择


在这项研究中，我们研究了俄罗斯自动登月任务“Luna-25”、“Luna-26”以及“Luna-27”航天器的科学目标和着陆地点。 “Luna-27”计划直接在南极地区着陆，由于弹道和工程要求，该地区仅限于东经51°至西经1°、南纬83°至79°的区域纬度为 S。该地区地形复杂，为了确定合适的着陆区域，考虑了坡度分布、光照度和地球能见度，创建了适宜性地图。研究区域内共有5个30×15公里（着陆椭圆）站点满足坡度分布小于7°～10°、日照照度大于35%、地球能见度大于50等科学技术要求%。所有着陆点根据月球土壤中氢水当量（WEH）的含量按优先级从 1 到 5 排列。 1 号站点因其特点被认为是最好的，可以选择作为主要着陆点，而 2 号和 3 号站点可以作为备用着陆点。事实证明，随着着陆精度的提高，与给定点的偏差概率达到 0.5 公里，主要满足科学而非工程技术安全标准（本质上也满足）的合适着陆点数量显着增加。